Cam construction



March 18, 1969 J. 1.. CASSELL 3,433,090

CAM CONSTRUCTION Filed April 6, 1967 1 N VENTOR. JOSEPH CA SSELL UnitedStates Patent Office 3,433,090 Patented Mar. 18, 1969 3,433,090 CAMCONSTRUCTION Joseph L. Cassell, New York, N.Y., assignor to AutomaticFire Alarm Company, New York, N.Y., a corporation of New York Filed Apr.6, 1967, Ser. No. 628,961

US. Cl. 74-567 Int. Cl. F16h 53/02 6 Claims ABSTRACT OF THE DISCLOSURECam for the control of fire alarm signals or for other purposescomprising a length of wire of predetermined circular extent on arotatable support, for effecting actuation of a switch lever or the likein desired timed relation according to the length and position of thewire on the rotatable support.

FIG. 4 is a plan view illustrating a form of the invention for effectingseparate intermittent actuation of switch levers or other devices.

FIGS. 5 and 6 are plan and edge views respectively of one of the camforming wires.

In the plan view, FIG. 1, the invention is shown applied to the controlcam of an automatic fire signal transmitter, which cam controls therecycling of the fire alarm signals sent out by the transmitter.

This cam, as illustrated, usually takes the form of a flat gear wheel 7,driven from the gear 8 of a clock escapement, and having on its face acam groove 9, engaged by a start and stop lever 10, cooperable with theshoulder 11 at the end of the cam groove.

In the present instance, the timing control cam 7 is utilized for thepurpose of controlling an additional circuit or circuits governed by thespring switch arms 12, 13, 14, FIG. 2.

This is accomplished by means of a length of spring wire 15, of circularformation, mounted on the face of the gear, in position to engage andlift the lowermost spring arm 12 sufficiently to cause lifter 16 on thatspring to raise spring arm 13 and close the upper, normally open circuitcontacts at 17 and to hold these contacts in such relation for a singlerevolution of the cam.

FIG. 1 illustrates the rest position of the parts with the V-shapedfollower 18 of the lower switch spring resting on the face of the gearajoining the starting end of the cam forming wire so that immediately onstarting the gear the switch spring will be lifted by the cam wire andheld in that relation for the full circular extent of the wire.

The cam forming Wire may be of different materials, but preferably is ofsome stiff spring material, such as Phosphor bronze.

Different methods of fastening it in place may be employed.

In the present illustration, it is secured by having the ends of thesame bent at an acute angle as shown at 19, FIG. 3 and passed throughopenings 20 in the gear and fixed in this relation by solder rings 21.

The bending of the ends of the wire at an acute angle tensions theoverlying circular portion of the Wire firmly against the flatsupporting surface of the gear.

If the gear disk or other rotatable support on which it is mounted isnon-metallic, the bent ends of the Wire may simply be bent over, rivetedor otherwise secured in place.

Where intermittent action is desired, a number of the Wire segments,possibly of the same or different lengths may be employed, asillustrated at 22, 23, 24, FIG. 4.

The rounded corners at the bent ends of the arcuate, circular portion ofthe wire provide desired approach inclines 25, for lifting and loweringthe switch spring, lever or other part engaged by the wire.

The wire may be of circular or other cross-section and of a diameter toimpart the desired lift to the switch lever or other actuated device.

The rotatable support may be in the form of a flat disc arranged tosupport the cam forming portion of the wire in a single fiat plane or itmay be contoured to other shape and the wire may be bent intodepressions or raised portions according to desired action of the cam.

The invention thus provides for the manufacture of cams to effectpractically any desired mechanical or electrical operation and this atsimple low cost construction.

While readily shaped to different cam formations, the stiff spring wirewill hold the shape given it under adverse working conditions.

Furthermore, it may be readily removed and be replaced by a freshlyformed wire or the old wire may be modified or changed in shape and beused in the new form as required to meet different conditions.

The wire thus constitutes a strand of cam forming material readilyadaptable to meet various cam requirements.

The rotatable support on which the wire is mounted, provides, at theends of the wire, the low or rest portions of the complete camstructure, and which rest portion may be flat as shown or given anyspecial shape for cooperation with the cam follower which may for example, be in the form of a cam roll.

What is claimed is:

1. A cam construction comprising the combination of a rotatable supportand a wire of cam forming material suitable for engagement by a camfollower secured in fixed position on said support,

said wire having an exposed cam face forming surface disposed in thedirection of rotation of said rotatable support.

2. The invention according to claim 1, which said support havingopenings therein spaced to locate the ends of the cam forming wire andsaid wire having angularly bent ends secured in said openings in thesupport.

3. The invention according to claim 2, with said openings extendingthrough said support and the ends of the wire being bent at acute anglesand extending entirely through the support and fastening elements at theterminal ends of the wire.

4. The invention according to claim 1, with said wire extending incircular formation and having angularly bent ends with rounded cornersleading to the ends of the circular portion of the wire.

5. The invention according to claim 1, with said cam being of stiffspring material and having acutely angled bent ends and, said supporthaving openings in which said acutely angled ends of the wire andengaged.

6. A cam construction comprising the combination of a rotatabledisk-like support forming the body of said cam construction,

said support having openings therein spaced circumferentially the lengthof the cam surface to be prothe face of said support by said angularlybent ends vided, embedded as described in said support.

a length of cam surface forming wire extending over the surface of saidsupport between said openings References Cited therein and terminatingin angularly bent ends ex- 5 UNITED STATES PATENTS tending through saidopenings and fixedly secured 4 13 11/1903 Gorman therein, 2,569,0969/1951 Geiger et al. 74567 said cam forming wire having rounded leads atthe junction of said angularly bent ends with the inter- FRED MATTERN,Primary Examine!- mediate length of the wire for engagement by a cam 10W. RATLIFF, JR Assistant Examiner follower and the intermediate portionof the wire between said angularly bent ends being shaped to v US. Cl.X.R. form the active cam surface and held fast against 3382; 73-885

